Traditionally, wood beams and other wood products have been cut from naturally grown trees. However, trees are limited in supply due to the years necessary for the trees to reach maturity, and particularly hardwood trees most suitable for lumber products. Also, the extensive harvesting of hardwood trees aggravates the increases in greenhouse gases such as carbon-dioxide and should be conducted on a managed basis.
One approach to this problem has been to produce composite lumber products formed out of wood scraps, inferior quality lumber materials, and even sawdust. Such processes generally utilize steps where wood pieces are coated with an adhesive and subjected to compression and heat to form a pressed composite assembly. This technique has been utilized to manufacture particleboard from small wood particles and to manufacture plywood from wood veneer sheets.
One process that has been developed is adapted to manufacturing structural wood products from long, relatively thin strands of wood, and involves coating the strands with adhesive, arranging the strands side-by-side in a length-wise dimension of the lumber product and subjecting the arranged strands to heat and compression. Using this technique, high strength dimensional wood products can be formed as reflected in U.S. Pat. No. 4,061,819. Similar products are disclosed as being manufactured from bamboo segments in U.S. Pat. No. 5,543,197.
The use of bamboo in lumber products is of particular interest due to environmental concerns. Bamboo is recognized as an environmentally friendly, sustainable and renewable resource. The pole of the bamboo plant typically grows rapidly and reaches full maturity in only 4-7 years. If the bamboo pole is not harvested, the pole dies and a new pole regenerates from the base of the original plant. For this reason harvesting the bamboo pole causes no harm or reduction in the growth of the bamboo plant or its absorption of carbon dioxide through growth. Factories manufacturing bamboo lumber products have traditionally been located in Asia near the bamboo plantations and forests, to minimize transportation costs of raw materials.
By moving away from the commodity types of limited color pallet bamboo product offerings in three foot lengths that have been produced in a traditional manner by simply gluing or pressing bamboo strips together, oriented strand or strand woven bamboo products have developed increasing popularity. Strand woven bamboo, produced through the use of adhesives and pressure, can be manufactured into extremely hard and durable products resulting in flooring that can be used for high traffic areas and that can be nailed, glued down, and floated and isolated from a subfloor to prevent contact with moisture. To this time, these engineered strand-woven bamboo products have been manufactured with limited variations in appearance, particularly by cutting the exposed surfaces to show either flat grain or vertical grain orientation. The market desires additional and more varied appearances from flooring products. In order to provide these appearances, some bamboo surfaces have been hand scraped, distressed or otherwise treated to create rustic effects, and stains have been applied to broaden the color pallet of strand woven bamboo products beyond the natural and caramelized colors traditionally offered for bamboo.
Another flooring material that is recognized as environmentally friendly is cork. Cork is harvested from the bark of oak trees in the Mediterranean, and primarily in Portugal. The bark is gently peeled from the trees every 7-10 years and the trees are not cut down or harmed in any way as they regenerate their bark over time. Some evidence suggests that harvested trees are more vigorous and have higher carbon dioxide absorption rates than trees left in their natural state. Much of the desirability of cork as a flooring or surface option is attestable to benefits provided in the areas of maintenance, insulation, resilience, impermeability and flame retardance. Cork's cellular structure provides a high resistance to liquid penetration, and 90% of cork's tissue is gaseous matter that makes for excellent thermal and acoustical installation. The cellular gas structure also allows a cork floor to recover quickly from pressure and provides a comfortable surface for walking and standing.